It's been one of the most remarkable F1 seasons ever. One of the best title battles of all time came down to the final lap of the final race -- and not without enormous controversy.
Over such a long season, which featured six different drivers and four different teams claiming a race victory, it was a year of big breakouts across the grid.
While fans are still debating whether Max Verstappen or Lewis Hamilton deserved the 2021 crown more, there were a number of drivers behind the championship fight who had standout campaigns.
Here's our top 10 for the season.
1. Max Verstappen
How do you split the two best drivers in the world? Even a season of 22 races didn't offer a satisfactory or definitive answer to that question, so picking Verstappen over Hamilton as ESPN's best driver of 2021 is likely to upset (and perhaps even enrage) some readers.
But there are a couple of key reasons. When the level is as high as it was between Verstappen and Hamilton this year, small mistakes carry more weight and consistency becomes everything. Removing Verstappen's retirements from the results (and the Hungarian Grand Prix in which Verstappen was taken out of contention by an incident triggered by Valtteri Bottas at the start) he never finished outside the top two. That includes the Russian Grand Prix where he had a grid penalty for an engine change (brought about by his collision with Hamilton at Silverstone) and the final four races of the season where Mercedes had a car capable of taking one-two victories.
What's more, thanks to his sprint race points in Great Britain and Italy, he scored points at every round bar the Azerbaijan Grand Prix where a tyre failure took him out of the lead of the race with a handful of laps remaining.
You can argue he was too aggressive at times, but that aggression also saw him pull off some of the most impressive overtakes of the year, including his lap one move around the outside of both Mercedes in Mexico and his pass on both Hamilton and Esteban Ocon in Saudi Arabia.
It's true that the circumstances in which he won the title were hard to accept, but none of what happened in Abu Dhabi was Verstappen's fault. Instead, he made sure he was in the running throughout the final race (as he had been throughout the season) to be in a position to capitalise on one last twist in the tale. That is the hallmark of a true world champion.
2. Lewis Hamilton
Of course, an equally strong case can be made for Hamilton to top this list. Over the balance of the races, Verstappen's Red Bull appeared to be the faster car, yet Hamilton ground out enough results that he would have been crowned champion had the end of the Abu Dhabi Grand Prix been handled correctly.
But while Verstappen never had an off race in 2021, Hamilton had the Monaco Grand Prix. It seems unfair to focus on one single low point in a remarkable year, but it is only because the standard between the top two was so high that Monaco stands out as a justification for putting Hamilton second.
Hamilton qualified and finished seventh at the street race on a weekend when his teammate Valtteri Bottas qualified third and was on target for a podium before a problem at his pit stop forced him to retire. The car clearly wasn't suited to the circuit, but it was the one time in the year when Hamilton looked decidedly average compared to the rest of the field.
Yet for the 21 other races, Hamilton was either on or occasionally above Verstappen's level as the best driver in F1. His performances toward the end of the year were on a remarkable level, and arguably one that we have not seen from Hamilton before. His victory in Brazil stands out as the best performance by any driver at any race this season, and had the Abu Dhabi Grand Prix been run to the rulebook, it would have marked the start of a remarkable comeback to win the title.
3. George Russell
It's often hard to judge the performance of drivers in backmarker teams, but Russell made it relatively easy in 2021 with a series of standout performances.
The two headline results were his qualifying performances in Belgium (second place) and Russia (third place). Because the race at Spa-Francorchamps was rained off, his qualifying result converted into a remarkable podium finish, which may not have been earned the traditional way but was no less deserved.
Rain is often considered the great leveller in F1, and undoubtedly Russell would not have been that high up the grid in the dry. But if you consider where Russell would have been in a car with more downforce, it's not absurd to suggest he might have qualified a second down the road from Verstappen and Hamilton. His performance in Russia was also impressive in difficult conditions, underlining that Spa wasn't a fluke and that Russell can lay claim to being one of F1's fastest drivers over a single lap.
Even so, it would still be a stretch to put Russell so high on this list on the basis of two performances in wet conditions. Fortunately, the vast majority of his qualifying performances over the year underline his brilliance in 2021.
Despite having the second slowest car in F1 at his disposal, Russell was only knocked out in Q1 on three occasions (not counting Austin where a grid penalty meant he opted not to compete) over 22 races. He consistently outperformed his car on Saturdays in a way that only the top two drivers on this list could hope to match.
In races it was always going to be harder to maintain that level of performance, but he still finished in the top 14 more often than not and, driving for a team that had scored just one point in the past two years, he notched up 16 points with four separate finishes in the top ten.
On the basis of his performances at Williams, his arrival at Mercedes next year should see him join the top two on this list in the fight for the title assuming the car is competitive enough.
4. Lando Norris
It's always important not to be led by recency bias when reviewing the season, and that's why Norris' lack of points toward the end of the season shouldn't eclipse his remarkable start to the year.
Up until the Hungarian Grand Prix where he was taken out by Bottas at the start while fighting for fourth place, he had finished in the top five positions at all bar one of the previous 10 races. When you consider that Mercedes and Red Bull had the performance to fill the top four positions at all of those rounds, that is hugely impressive.
By the end of the year he finished in sixth place behind Carlos Sainz in the standings, but that only tells a small part of the story of his season. His peak performances were way higher and on a number of occasions he missed out on points by pushing right to the edge, such as his qualifying crash in the wet at Spa-Francorchamps.
Another obvious example was the Russian Grand Prix, which he would have won had McLaren properly communicated the threat of rain to Norris at the end of the race. In Hungary he would also have been on for a good result had he not been taken out by Bottas, in Brazil a good finish was on the cards had it not been for a tangle with Charles Leclerc on the opening lap and in Saudi Arabia a red flag ruined his chance of a good result. Remove any one of those bits of bad luck and he would have finished in fifth place in the standings.
And that's without even mentioning how he outperformed his highly rated teammate Daniel Ricciardo over the course of the season.
5. Carlos Sainz
Consistency was the key for Sainz in 2021 and it earned him a best-of-the-rest fifth place finish in the drivers' championship. He scored points in 20 of the 22 races (only Hamilton and Norris achieved the same feat) and took four podiums, with his second place in Monaco as the high point.
Picking between Sainz and his Ferrari teammate Charles Leclerc was not easy. While Sainz scored more points throughout the year, arguably Leclerc's high points, such as his pole position in Monaco, were higher.
But when you consider that Sainz started from zero at Ferrari after joining the team from McLaren over the winter, his performances are the more impressive in 2021. Either way, Ferrari can now claim to have one of the strongest driver pairings in F1.
6. Charles Leclerc
It was an odd year for Leclerc in which he always seemed to be on the brink of brilliance without ever really reaping the rewards.
He scored just one podium over the 22 races but finished fourth on five occasions in Imola, Barcelona, Monza, Turkey and Austin. He had genuine shots at winning two races in Monaco and Silverstone, but in Monaco his driveshaft broke on the way to the grid after he hit the wall in qualifying and in Silverstone Hamilton just beat him to the flag after recovering from a collision with Verstappen and a 10-second time penalty.
He held a slight qualifying performance advantage over Sainz throughout the year, but considering he was the incumbent at Ferrari and so fast compared to Sebastian Vettel last year it was perhaps not as big as many expected.
7. Fernando Alonso
It took a handful of races for him to hit his stride, but once Alonso was up to speed he looked every bit the brilliant competitor that he was in his prime. The early cobwebs can be explained by the combination of his preseason cycling accident and just one and a half days of testing in Bahrain before the season opener, but by the end of the year he was getting the most from the Alpine.
Traditional Alonso traits such as remarkable racecraft and his impressive ability to read a grand prix from the cockpit were evident on a number of occasions, but no more so than in Hungary where he held up Hamilton for 11 laps to help teammate Esteban Ocon win the race. He got his own podium reward in Qatar after a brilliant performance on old tyres to take third place behind the top two drivers in the sport, Verstappen and Hamilton.
Given a competitive car, it would be brave to bet against Alonso in a straight fight with any driver on this list.
8. Pierre Gasly
It was no longer a surprise to see Gasly's AlphaTauri on the front three rows of the grid in 2021 as he continued to make a case for a return to the senior Red Bull team by qualifying in the top six more often than not. He dominated his teammate Yuki Tsunoda over the course of 22 races and was only outqualified once by the rookie at the final round.
But by the end of the season there was still a question over whether he got the most from the AlphaTauri.
Quite often the car looked like a true competitor with McLaren and Ferrari, yet Gasly's race results over the course of the year didn't back that up. There were missed opportunities and mistakes -- losing his front wing in collisions in Bahrain and the Monza sprint race, for example -- and on occasion Gasly simply went missing in the races, such as his drop from second on the grid in Qatar to 11th at the finish.
He is clearly one of the most gifted drivers on the grid, and one who deserves another shot in race winning machinery, but there was still room for improvement.
9. Esteban Ocon
Ocon's race win in Hungary was a standout performance that earns him a place on this list. It came at a time when he needed it most, having scored just two points from five races in a mid-season lull shortly after securing a new contract, and it helped to prop up a points tally that may have looked a bit thin by the end of the year without it.
But when you consider that the Alpine was not really a top 10 car at most circuits -- with the Red Bull, Mercedes, Ferrari, McLaren and AlphaTauri all looking superior in terms of outright performance -- he still managed to finish in the points more often than not over the course of the year.
At the start of the season he appeared to have the measure of teammate Alonso, but as the two-time champion got up to speed the advantage swung back and forth between the two. Ocon will need to retake the upper hand in that relationship next year to prove his victory in Hungary was the first of many rather than a one-off.
10. Sebastian Vettel
By the end of 2020, Vettel was a shadow of his former self as he was comprehensively outperformed by Ferrari teammate Leclerc. Moving to Aston Martin was an opportunity for a fresh start but ran the risk of him looking decidedly average against another young teammate in Lance Stroll.
Due to regulation changes over the winter, Aston Martin struggled for performance throughout the season and at first Vettel's decline looked in danger of continuing. He failed to score points at the opening four races before a breakthrough performance in Monaco kick started his season. A podium followed at the Azerbaijan Grand Prix and there would have been another at the Hungarian Grand Prix had enough fuel been left in the tank to provide a sample to the FIA after the race.
It was far from a vintage year for Vettel, but there were signs of a recovery and he finished nine points clear of Stroll, which would have been 27 had he not been disqualified in Hungary.